Computer program Neutron-CR-39 for simulation of neutrons from an Am-Be source and calculation of proton track profiles

Abstract

A computer program called Neutron-CR-39.F90 for neutron simulation through a PADC detector and its detection was described and developed. In this work the neutron Am-Be source was considered for simulation. It was shown that the most intensive secondary particles, created in neutron interactions with the detector, are protons. The programming steps are outlined with detailed description of neutron simulation, determination of latent tracks of created protons, as well as, their development after detector etching in the same and opposite direction of particle motion. The outputs of the code are parameters of created protons (coordinates of starting and stopping points, direction angles of particles, initial and deposited energies) and number of visible tracks per incident neutron. Program summary: Program title: Neutron-CR-39 Catalogue identifier: AEIU-v1-0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ AEIU-v1-0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 140 004 No. of bytes in distributed program, including test data, etc.: 2 213 012 Distribution format: tar.gz Programming language: Fortran 90 Computer: PCs and workstations Operating system: Unix, Linux, Windows 95+ RAM: 256 MB Classification: 17.5, 18 External routines: For the Windows installation the entire code must be linked with the PORTLIB library. Nature of problem: The neutrons do not cause ionizations in the detector, and consequently no tracks are produced directly by them in the PADC. Due to the elastic and nonelastic interaction of neutrons with the atoms of PADC, recoil nuclei and secondary particles are created producing latent intrinsic tracks. After chemical etching in aqueous NaOH solution these tracks become visible under optical microscope and usually density of visible tracks is measured. Optical microscopes are often used for this purpose but the process is relatively tedious and time consuming. The present computer program has been written for neutron simulation through PADC detector; determination of parameters of secondary particles; calculation track profiles of secondary particles emitted in the same and opposite direction as etchant progression. The outputs of the code are parameters of secondary particles (coordinates of starting and stopping points, direction angles of particles, initial and deposited energies) and number of visible tracks per incident neutron. Solution method: A computer program is prepared to simulate neutron's interactions in a PADC by the Monte Carlo method using the Neutron data library ENDF/B-VII [B. Milenkovic, D. Nikezic, N. Stevanovic, Radiat. Meas. 45 (2010) 1338]. The parameters of the emitted secondary particles (emission angle, initial energy, deposited energy and starting and stopping coordinates) were stored in an enclosed file. The subroutine for calculation of track profiles by a finite difference method for particles emitted in the same direction was developed [D. Nikezic, N. Stevanovic, D. Kostic, S. Savovic, K.C.C. Tse, K.N. Yu, Radiat. Meas. 43 (2008) S76]. It was shown that there are many tracks formed in the opposite direction than the etchant progression. The method for calculation of track profiles for these particles is developed in [B. Milenkovic, N. Stevanovic, D. Krstic, D. Nikezic, Radiat. Meas. 44 (2009) 57]. It is very different than the method for track in the same direction. The separate subroutine for this purpose was developed here. Additional comments: The program distribution file contains an executable which enables the program to be run on a Windows machine. The source code is also provided, but in order to build an executable the PORTLIB must be available. Running time: Running time depends mainly on the neutron number for simulation, source and detector geometry and removed layer required by the user. Running time is several minutes. © 2011 Elsevier B.V. All rights reserved.